From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5EFBACDB481 for ; Fri, 14 Nov 2025 03:49:33 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vJknq-0004Pz-GP; Thu, 13 Nov 2025 22:48:50 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vJknn-0004Ob-Dm for qemu-devel@nongnu.org; Thu, 13 Nov 2025 22:48:49 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vJknl-0003Vj-JY for qemu-devel@nongnu.org; Thu, 13 Nov 2025 22:48:47 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1763092125; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xESHkyCgDZUuElSFICc3k0Xt2tWmu58rcuZH0lYtxR8=; b=NCgqRvuzVbaWZAyiskBQGUFngZbyw0z/y2oOdmcQ3L9mv6vUbIUB0bXd2Zk2Yd9baZXtsw xSUUN8WW4eX+gtbLpmKgG9Yj/vKt4m/iW3MWDb/KwS3FYGS/oAFdt6oYimwUNgaq5FL5By zQOYq3zalghbfRSzdri2MA9OSRB9NdE= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-516-Q7j3h3mwNGKBR6T-y9DWLw-1; Thu, 13 Nov 2025 22:48:43 -0500 X-MC-Unique: Q7j3h3mwNGKBR6T-y9DWLw-1 X-Mimecast-MFC-AGG-ID: Q7j3h3mwNGKBR6T-y9DWLw_1763092122 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 3CCEF180048E; Fri, 14 Nov 2025 03:48:42 +0000 (UTC) Received: from localhost.localdomain (unknown [10.72.120.9]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 1A94618002B6; Fri, 14 Nov 2025 03:48:37 +0000 (UTC) From: Jason Wang To: qemu-devel@nongnu.org Cc: Peter Maydell , qemu-stable@nongnu.org, Akihiko Odaki , Jason Wang Subject: [PULL 5/5] net: pad packets to minimum length in qemu_receive_packet() Date: Fri, 14 Nov 2025 11:48:06 +0800 Message-ID: <20251114034806.2440-6-jasowang@redhat.com> In-Reply-To: <20251114034806.2440-1-jasowang@redhat.com> References: <20251114034806.2440-1-jasowang@redhat.com> MIME-Version: 1.0 Content-type: text/plain Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.133.124; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Peter Maydell In commits like 969e50b61a28 ("net: Pad short frames to minimum size before sending from SLiRP/TAP") we switched away from requiring network devices to handle short frames to instead having the net core code do the padding of short frames out to the ETH_ZLEN minimum size. We then dropped the code for handling short frames from the network devices in a series of commits like 140eae9c8f7 ("hw/net: e1000: Remove the logic of padding short frames in the receive path"). This missed one route where the device's receive code can still see a short frame: if the device is in loopback mode and it transmits a short frame via the qemu_receive_packet() function, this will be fed back into its own receive code without being padded. Add the padding logic to qemu_receive_packet(). This fixes a buffer overrun which can be triggered in the e1000_receive_iov() logic via the loopback code path. Other devices that use qemu_receive_packet() to implement loopback are cadence_gem, dp8393x, lan9118, msf2-emac, pcnet, rtl8139 and sungem. Cc: qemu-stable@nongnu.org Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3043 Reviewed-by: Akihiko Odaki Signed-off-by: Peter Maydell Signed-off-by: Jason Wang --- net/net.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/net/net.c b/net/net.c index 27e0d27807..8aefdb3424 100644 --- a/net/net.c +++ b/net/net.c @@ -775,10 +775,20 @@ ssize_t qemu_send_packet(NetClientState *nc, const uint8_t *buf, int size) ssize_t qemu_receive_packet(NetClientState *nc, const uint8_t *buf, int size) { + uint8_t min_pkt[ETH_ZLEN]; + size_t min_pktsz = sizeof(min_pkt); + if (!qemu_can_receive_packet(nc)) { return 0; } + if (net_peer_needs_padding(nc)) { + if (eth_pad_short_frame(min_pkt, &min_pktsz, buf, size)) { + buf = min_pkt; + size = min_pktsz; + } + } + return qemu_net_queue_receive(nc->incoming_queue, buf, size); } -- 2.42.0